Lesson Notes By Weeks and Term v4 - SHS 1
THE HUMAN BODY AND HEALTH
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THE HUMAN BODY AND HEALTH
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Subject: General Science
Class: SHS 1
Term: 1st Term
Week: 20
Grade code: 2.3.3.LI.2
Strand code: 4
Sub-strand code: 1
Content standard code: 2.3.3.CS.1
Indicator code: 2.3.3.LI.2
Theme: RELATIONSHIP WITH THE ENVIRONMENT
Subtheme: THE HUMAN BODY AND HEALTH
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This lesson explores one of the most vital systems in our body: the Nervous System. Think of it as the body's 'management team' and 'communication network' all in one. It controls everything we do, from thinking and feeling to moving and breathing. In our daily lives in Ghana, our nervous system is constantly at work. It helps a driver on the Accra-Kumasi road react quickly to a pothole, allows a student to understand and answer a question in class, and enables a market woman to calculate change for a customer. Understanding how this system works is fundamental to understanding our health and how we interact with our environment.
A. The Structure of the Nervous System
The human nervous system is a complex network of specialised cells called neurons that transmit signals between different parts of the body. It is the body’s primary control and communication system. It is organised into two main parts: Central Nervous System (CNS): This is the main control centre. It consists of the brain and the spinal cord. Peripheral Nervous System (PNS): This consists of all the nerves that branch out from the brain and spinal cord to all other parts of the body, like the arms, legs, and internal organs. It acts as the messenger, carrying information to and from the CNS.
Think of it like a school's administration: CNS (Brain & Spinal Cord) = The Headmaster and Assistant Heads (making decisions and processing information). PNS (Nerves) = The school messengers and notice boards (carrying instructions to students and bringing feedback to the administration). B. The Central Nervous System (CNS) The Brain The brain is the command centre of the body, protected by the skull. It is responsible for thought, memory, emotion, and controlling bodily functions. For SHS 1, we will focus on three major parts: Cerebrum: Description: This is the largest part of the brain, divided into two halves (hemispheres). It has a folded surface. Function: It is the centre for intelligence, memory, learning, reasoning, and consciousness. It also controls all voluntary actions (actions we choose to do). Ghanaian Example: When you are solving a Core Mathematics problem, remembering the directions to your friend's house, or deciding to kick a football, you are using your cerebrum. Cerebellum: Description: Located at the back of the brain, beneath the cerebrum. Its name means "little brain." Function: It is responsible for balance, posture, and coordination of muscular movements. It ensures our movements are smooth and precise. Ghanaian Example: A student dancing *Azonto* or *Adowa* needs their cerebellum to coordinate the complex steps and maintain balance. A person riding a bicycle or an Okada relies heavily on their cerebellum. Medulla Oblongata (part of the Brainstem): Description: Located at the base of the brain, connecting it to the spinal cord. Function: It controls all involuntary actions – the vital functions that keep us alive without us having to think about them. These include heartbeat, breathing rate, and digestion. Ghanaian Example: You don't have to remind yourself to breathe while sleeping or tell your heart to beat faster when you are running for a tro-tro. The medulla oblongata handles this automatically. The Spinal Cord Description: A long, thin bundle of nervous tissue that extends from the medulla oblongata down the back, protected by the vertebral column (backbone). Function: Information Highway: It acts as the main pathway for nerve impulses to travel between the brain and the rest of the body. Reflex Centre: It controls simple, rapid, and automatic responses called reflex actions. C. The Peripheral Nervous System (PNS)
The PNS connects the CNS to the limbs and organs. It is further divided into two parts based on function: Somatic Nervous System: Controls voluntary movements of skeletal muscles. Example: Writing notes, waving to a friend, walking to the dining hall. You are in conscious control. Autonomic Nervous System: Controls involuntary actions of internal organs and glands. Example: The widening or narrowing of your pupils in response to light, sweating on a hot day in Accra, or the increase in your heart rate when you are frightened. You have no conscious control over these. D. The Reflex Action and Reflex Arc